Common Diseases and Pests of Rose in Autumn
An article about green plant knowledge, introducing the related introduction of rose, common diseases and pests of rose in autumn. Next, the editor will introduce them.
In the cool autumn, some common diseases and pests of roses reappear. It is necessary to understand and prevent and treat these diseases and pests in time:
1. Powdery Mildew: The disease occurs on the new branches, tender leaves, young buds, and flower buds of the affected plants, covered with greyish-white mycelium, from dots to sticky white powder. The affected large rose plants bend the upper branches, deform the flowers, and the small branches and leaves wither and even die. Spray with 50% thiophanate-methyl 1000 times liquid or 50% carbendazim 500 times liquid, and remove dense and intersecting small branches to maintain ventilation and light.
2. Black Spot: Dark brown spots first appear on the lower leaves, then gradually increase and become circular black spots with a diameter of 3-10 millimeters, causing the leaves to turn yellow and fall off.
3. Brown Spot: It looks similar to black spot disease, with elliptical or irregular brown or dark brown spots, and unclear outlines. The course of the disease is the same as black spot disease, and both are prevented and treated with thiophanate-methyl or carbendazim sprays.
4. Withered Branch Disease: Purplish-brown spots appear on green branches, gradually expanding into pieces, and finally becoming greyish-white, with the branches drying and dying. The cause of the disease is often due to unripe or excessive use of organic fertilizer. If a small number of branches are affected, the diseased branches can be cut off and burned. When many branches are affected, spray with metam sodium or lime sulfur mixture.
5. Root Cancer: It usually occurs in plants over two years old, with tumors 1-5 centimeters in size at the rootstock under the surface soil, which is root cancer. The disease is caused by soil-borne pathogens entering through wounds in the roots of the rose. There is currently no good method of control. The common method is to cut off the affected area and burn it, apply a little sulfur powder to disinfect the incision, and then replace the potting soil.
6. Aphids: Mainly large tubular aphids and mealy aphids. Aphids hide on the back of leaves, absorb sap, causing the plant to grow slowly, young leaves to curl, and affecting flowering. Spray with 40% dimethoate 1000 times liquid or 80% dichlorvos 1000 times liquid. Aphids multiply rapidly and must be controlled in time.
7. Red Spider Mites: They lurk on the back of leaves, spin webs,刺吸 leaf sap, causing the leaf surface to dry and turn yellow, and even wither and fall off. Spraying with 800 times liquid of dicofol has a special effect, and it can also be treated with dimethoate, methidathion, and dichlorvos.
The above introduction of common diseases and pests of roses in autumn, hoping to bring some flower knowledge to flower enthusiasts.